The glamour model caused two other vehicles to move away as she drifted into their lane on the A23 in West Sussex on February 19, magistrates were told.

Prosecutors said that Katie, 32, was seen on the phone for two to three seconds by two officers after they drove alongside her in a patrol vehicle following the “careless” manoeuvre.

Pc Phill Mann, of Sussex Police, told Mid Sussex Magistrates’ Court in Haywards Heath that he saw Price making a texting motion on an iPhone-type handset before pulling her over.

Price, married to cagefighter Alex Reid, who was also in the vehicle, denied using a mobile phone and told the officer she had been spraying perfume, Pc Mann said.

She denies not being in proper control of a vehicle.

Price, dressed in a fur-trimmed coat and black leggings, sat on a bench behind her lawyer, Nick Freeman, nicknamed Mr Loophole, as the evidence was heard. The court was shown footage captured by police apparently showing Price veering slightly across the carriageway while at the wheel of the horsebox.

Prosecutor Rachel Beckett said the officers saw the distinctive vehicle on the A23 at a location known locally as Jeremy’s Corner at 11.55am.

She said: “Pc Mann observed a vehicle which he saw drifting slightly into lane two from lane one. Pc Mann drove up next to the vehicle and saw Miss Price was driving and saw that she was using a mobile phone.

When the defendant saw the police car, she held the device down. Pc Mann’s colleague, PCSO Mitchell, also saw Miss Price using the mobile phone for some two to three seconds.”

When Price, who also had children in the vehicle, was pulled over, she told Pc Mann that they had seen a perfume bottle and not a mobile phone, the court was told.

She retrieved a large bottle of perfume from a bag and showed it to Pc Mann, who told her that it was not what had been seen in her hand moments earlier. Ms Beckett said Price also showed the officer her mobile phone covered in coloured stones.

Pc Mann told the court: “I saw a person who I know to be Katie Price in the driver’s position and in her right hand she had what appeared to be a mobile phone.

She had her thumb on the phone, and appeared to be texting. It was slim, black and palm-sized, like an iPhone. I think that’s what I saw.